Instead of exposing photosensitive film that must be developed in a photographic laboratory, electronic or digital cameras use an electronic image sensor array, such as a CCD (Charge-Coupled Device) array, to capture an image focused on the array by a lens assembly by generating electronic image data from the image sensor array and storing the image data in an electronic storage medium. Consequently, it is possible for the operator to view a captured image immediately after the image data is created.
As a result of this capability, most digital cameras on the market include a color LCD (liquid crystal display) device, usually integrated into the back of the camera body. In addition to viewing stored images, the LCD is used to “frame” images for capture, similar to the viewfinder in a conventional photographic film camera. In fact, while most present day digital cameras include a conventional viewfinder, many if not most digital camera operators use the camera's LCD to compose images for capture. To view such images, the digital camera converts the image focused on the camera's image sensor device into electrical image data signals that are sent directly to the LCD. Such image data signals are sent to the LCD continuously and in rapid succession, such that the displayed image on the LCD appears as a live video image. Such a display is typically known as a “live view” to denote that the image being displayed corresponds to the instantaneous images being received by the lens assembly. The user may capture a “live view” image by actuating the shutter button, which causes the image sensor device to generate electronic image data that is then stored in the camera's storage medium.
Typically, the image captured and stored is temporarily displayed on the LCD for a few moments immediately after capture, subsequent to which the display returns to “live view” to enable the user to compose another picture. If the user wishes to review or study the image just captured, or show the captured image to others, it is necessary with prior art digital cameras to switch the camera from a “record” or image capture mode to a “playback” or stored picture display mode. This is usually accomplished either by rotating a function dial on the camera body from a “record” position to a “playback” position, or by moving a function switch between analogous positions.
Thus, a user taking a series of pictures who desires to review image capture results is required to switch the mode of the digital camera between “record” and “playback” each time that an image is captured and stored. This is a significant shortcoming in the art. This further presents a source of confusion and frustration to the user in a number of circumstances. The user who forgets to switch the camera back to record mode after having viewed a stored image will be unable to capture a desired image by pressing the shutter button, thereby possibly completely losing the opportunity to capture a fleeting image. Similarly, the user viewing the temporary display of a captured image is frustrated when the LCD reverts to live view, should the user wish to continue viewing the last captured image. Further, because conventional photographic film cameras do not have the capability of viewing photos, such cameras are always in a “capture” mode and camera users are conditioned to expect the same behavior from digital cameras. Because of this the different switchable modes of a digital camera may confuse many users.
Prior art attempts to solve such problems are known. U.S. Pat. No. 6,137,534 discloses the provision of an automatic “instant review” mode whereby a last captured image in an image capture device is displayed in a “screennail” format immediately after capture, while image processing is still being carried out, However, it is necessary for the user to consciously switch to this mode, and the user still must switch back to a “live mode” in order to continue taking pictures. U.S. Pat. No. 6,184,930 discloses a two-level push button switch for carrying out a first switching operation to capture and store a displayed image in memory, and a second switching operation for displaying the last stored image data. However, the image capture device still must be switched between image capture mode and playback mode to view other stored images, and the user is required to properly actuate the different levels of the push button in order to view a last captured image.
There thus exists a need in the art for further improvements to digital cameras to eliminate the shortcomings mentioned.